You probably associate getting older with a loss of energy. And on the molecular level, this is quite literally true. One of the hallmarks of aging is mitochondrial dysfunction. Mitochondria are often referred to as “the powerhouse of the cell,” because they convert nutrients from the food we eat into usable energy, in the form of ATP. But as we age, mitochondria become less effective at generating the energy we need for various chemical processes. So why does this happen? As with most things in biology, there are definitely multiple factors at work here. But one likely reason is a failure of quality control. Mitochondria are dynamic structures. They engage in repeated cycles of fission and fusion, not unlike bacteria. Both of these processes are essential, but they need to be kept in balance. And therein lies the trouble. As we age, mitochondrial fusion tends to predominate, and fission is diminished. This eventually leads to the accumulation of gigantic, broken mitochondri